Apparatus for treating wells



Jan. 19, 1943. o. E. BARSTOW APPARA'FUS FOR TREATING WELLS Filed Aug. 28, 1940 INVENTOR ORMOND E. BARSTOW W ATT QMM ORNEY$ a other in such a manner than one zone and sirable in the case of an acid Patented Jan. 19, 1943 UNITED" STATES, PATENT OFFICE a asossos mans-ms roamans'rnve wants Ormond E. Bar-stow, Midland. Mich assignor to The Dow Chemical Company, corporation of Michigan Application August 28, 1940,

3Claims.

The invention relates to apparatus for treating wells, such as oil, gas, brine, or water wells, whereby a fluid treating agent may be simultaneously introduced into at least two zones or strata while said zones are sealed oil from each that the fluid agent in the well bore about to enter one zone is maintained out of contact with the fluid. about to enter the other zone or zones. It more particularly concerns an apparatus for treating wells whereby the fluid treating agent being simultaneously introduced into at least two zones is controlled in such a manner that the rate of flow of fluid to each zone may be varied as desired during the course of the treatment.

The term zone" used herein and in the ap-""" pended claims is intended to refer to separately defined strata as well as to portions or sections of the same formation or stratum.

The bore of a well oftentimes penetrates more it is usually desirable when treating such wells with a fluid treating agent, such as for example an acid, to control the rate at which the treating fluid is entering each zone during the course of the treatment. This is detreatment because one zone may become highly porous during the course of the treatment and absorb practically all of the treating agent with the result that waste of the acid occurs and the most desirable results as regards the permeability are not obtained. It is further desirable when treating such wells that the introduction of fluid agentinto each stratum take place simultaneously in order to avoid the necessity of carrying out a separate treatment for each stratum.

It is; therefore, the principal oblect of the invention to provide an apparatus whereby fluid be simultaneouslyintroducedtreating agent may into each of more than one zone penetrated by the bore of a well.

Another object of the invention is to provide means whereby the rate of flow of a fluid treating agent being simultaneously injected into at least two zones may be varied during the course of the treatment so that the fluid may be caused to enter a selected zone at a faster or a slower rate.

Still other objects and advantages will be apparent as the description of the invention proceeds.

The invention then resides in the apparatus hereinafter more fully described and particularly pointed out in the claims, the following descripmost eflective increase in is shown Midland.

Mich, a

Serial No. 354,508

tion and accompanying drawing setting forth in detail a mode of carrying out the invention, such mode illustrating, however, but one of various ways in which the invention may, be put into operation.

In the accompanying drawing the Figure 1 is a fragmentary view in vertical cross section of a well bore showing an embodiment of the invention.

Figure 2 is a fragmentary sectional view of that portion of tubular eludes the discharge port or oriflce l3. and illustrates additional elements associated with the orifice which act to modify the action of said discharge oriflce.

,Figure 3 is a cross-sectional view taken alon lines 33 of Figure 1 looking in the direction of the arrows.

As shown, the lower portion i of the well bore penetrates a productive zone 2, an impervious non-productive zone I, and ends in a second productive zone}. Conventional well tubing I extending into the well and is attached to a tubular conduit member 6 by means of a conventional coupling I. Tubular conduit member 6 is provided at its upper end with an enlarged downwardly tapered shoulder 8 which serves as'a guide member for weight 9, which is adapted to be raised and lowered in the well by means of wire line or cable It, extending to the surface. The tubular conduit member 8 is attached at its lower end to second tubular member ll by means of a conventional coupling I to the wall of the rod is caused to move designated by numeral 1A. Tubular member ii is provided with threaded bosses I2, with which orifice members l3 and M are in screw threaded engagement. Below the threaded bosses It, a plate member I! having an opening I6 is held tubular member H as by welding. The plate member. supports an upwardly projecting U shaped guide bar l1, which will be more clearly seen in Figure 3. Guide bar i1 is provided with opposed openings which are threaded and engage the threaded rod or plug member IS. The rod i8 is provided at either end with tapered end portions which are adapted to engage the tapered openings in the oriflce members I! and It in sealing relationship as laterally in supporting bar 11. The threaded rod I8 is secured to pinion gear I! which is adapted to be actuated by rack 20, thereby causing the threaded rod it to move laterally sov as to seal the ports in either oriflce member ll or I as the rack slides Secured to the in plate I! and guide bar 11.

conduit II which inupper end 01' rack 20 ported plate member 2| acts to limit the extent of upward travel of the rack 20 as it contacts the enlarged shoulder 8 oi tubular element 6. The plate member 2| also serves as a surface for engagement with the weight 8 which acts to actuate the rack. In addition the plate member 2| acts to guide the rack 20 keeping it properly positioned in plate I! and guide bar IT. A second ported plate member 22 is attached to the wall of tubular member II at a point above the orifice members I3 and I4 and is provided with an opening located therein which allows the rack to slide therethrough. The plate 22 also acts as a seat for spring 23 which is confined at its upper end by plate member 2|. Thus the spring pressing against'both plates 2| and 22 acts to actuate the rack upwardly through the guiding plates l and 22 and guide bar I1. A circular plate 24 engages tubular element H at apoint below the lower limit of travel of the rack 20 and serves as a seal, preventing the flow of fluid downwardly in conduit ll. Orifice member |4 communicates with conduit through conduit 25 at a point below the sealing plate 24 and provides a means whereby fluid escapes into the well bore below packing element 28 while orifice member I! communicates with the well bore adjacent productive stratum 2. A conventional packing device 28 surrounds conduit II at a point below the sealing plate 24 and acts to seal productive stratum 2 from productive stratum 4 exteriorly of conduit Conduit extends below the packing device and communicates with the well bore through port 21. The lower end of conduit II is capped oil. by means of conventional cap 28.

In the fragmentary view shown in Figure 2, the orifice I3 is shown equipped with a back pressure valve assembly. The housing 2! of the valve assembly is shown attached to tubular element l I, as by welding. The valve assemblyconsists of a ported housing 28 having a well 30 in which valve stem 3| slides as pressure applied interiorly of conduit overcomes the pressure oispring 32 acting to force the valve into sealing relationship against the port in orifice member is.

The view shown in Figure 3 shows the guide bar I! and rack 20 in cross section more clearly illustrating their structure.

The method of the invention will be best understood from the following description, wherein the apparatus illustrated in Figure 1 is employed to carry out an acid treatment for the simultaneous injection of acid into separately defined strata, while the rate of fiow of acid to each stratum is controlled during the entire time 01' treatment. With the apparatus positioned as shown'in the drawing, a quantity of acid is started into the well through tubingi. The acid flows downwardly and discharges through the orifices in orifice members it and II. The acid from orifice member I: flows into the well bore at a point above the packing element 28 and enters stratum 2 while the member I4 is carried by conduit 25 to the space below the packing element 26 and enters productive stratum 4. If desired, a pressurlng fluid such as 011 (not shown). may be maintained in the annular space outside oi the well tubing 5 to control the height to which the acid rises in the well bore during the treatment. Pressure mayv be applied on the acid to displace it into the formation as by pumping in an additional quantity of acid into the well through the tubing. As

the treatment continues, the rate of flow to either acid flowing out of orifice.

particular reference to an acid treatment, it is 1 In the above manner stratum above and below the packer may be varied to any desired degree by raising and lowering the weight 9, carried by wire line It on plate 2|. This actuates the rack 20 and causes the threaded rod it to move laterally so as to vary the rate of flow of fiuid through the orifices. If desired, the weight 9 may be raised or lowered until one of the orifices is completely sealed or positioned at any point to give the desired flow.

The position of the rack and consequently the position of the two plug members may be determined by measuring the vertical distances traversed by the wire line, or, ii desired, the. position or the rack may be determined by measuring the tension on the wire line. This tension will decrease as more and more weight is applied to actuate the rack downwardly. By suitable calibration, the relationship between line tension and rack positions'can be determined, and thus the position of the plug members can be read in terms oftension on the wire line. In the foregoing manner, the rate of flow of mud to each stratum is susceptible of control during the course of an acid treatment.

In some instances it may be desirable to employ the spring loaded back prssure valve-assembly in conjunction with the discharge orifices or ports. The back pressure valve or the like associated with the discharge ports is desirable in those instances where formation pressures difi'er widely between the various strata or zones. By employins a back pressure valve in conjunction. with the discharge orifice, difi'erences in formation pressure can be compensated for by the valve thus aivins more control of the rate of flow through each orifice.

The method will be round to have most general use in connection with an acid treatment wherein a solution oi hydrochloric or other acid is introduced into the formation to bring about solution of the earth or rock formation and thus an increase in the size of the flow channels through which the desired mineral fluid flows to the well. In such treatments it will chloric acid of from-5 to 25 per cent concentration. Ii desired such an acid may be inhibited against corrosive attack upon iron orst'eel in the manner taught int). 8. Patent No. 1,877,504.

Although the method has been described with to be understood that any fluid treating agent may be introduced in accordance with the method oi the invention. Examples of such treating agents are paraflin solvents, liquid sealing agents, and the like.

a fluid treating agent may 1 be simultaneously introduced into two or more strata or zones of a productive nature and at the same time the rate of fiow of fluid to each zone is susceptible of control at all times during the treatment. a I claim:

1. In a well treating device for the simultane f'f ous injection or a fluid agent into at least two...-

bore oi a well. the com-' zones penetrated by the bination of a conduit having openings therein, a spring pressed rack carried bysaid conduit,

' a gear member adapted to mesh with said rack,

usually be found preferable to employ an aqueous solution of hydroface so as to cause the rack to move downwardly against the pressure of the spring. and sealing means surrounding said conduit at a point between the openings in the conduit adapted to seal the annular space between well bore and the conduit at a point intermediate the zones to be treated. V

2. In a well treating device for the simultaneous injection of a fluid agent into at least two zones penetrated by the bore of a well, the combination which includes a conduit having openings therein, a spring pressed rack carried by said conduit, a gear member adapted to be actuated by the rack, plug members associated with the gear member adapted to move laterally to engage either opening in the conduit in sealing relationship, a wire line operated weight adapted to be lowered into the well through said conduit from the suriace of the earth so as to cause the rack to move downwardly against the pressure of the spring. sealing means surrounding said conduit at a point between the openings in the conduit adapted to seal the annul-ar space between the conduit and well bore at a point between the zones to be treated, and a back pressure valve associated with one of the openings in said conduit adapted to open upon application of pressure to the interior of the conduit.

3. In a well treating device for the simultaneous injection of a fluid agent into at least two zones penetrated by the bore of a well, the combination comprising ,aconduit adapted to be disposed into the well bore, said conduit having openings therein communicating with the well bore and control means associated with the said openings adapted to be manipulated by a weighted wire line so that varying the tension on the wire line actuates the control means to vary the rate of flow of fluid through the openings, and sealing means surrounding said conduit adapted to seal the annular space'between go the well bore and the conduit.

ORMOND E. BARSTOW. 

